External Raw

Type: external-raw

The external-raw data source allows an external program to act as a data source, exposing arbitrary data for use elsewhere in the Packer configuration.

Warning This mechanism is provided as an "escape hatch" for exceptional situations where a first-class Packer provider is not more appropriate. Its capabilities are limited in comparison to a true data source, and implementing a data source via an external program is likely to hurt the portability of your Packer configuration by creating dependencies on external programs and libraries that may not be available (or may need to be used differently) on different operating systems.

Example Usage

data "external-raw" "example" {
  program = ["rev"]
  query = "hello"
}

locals {
  result = data.external-raw.example.result
}

source "null" "example" {
  communicator = "none"
}

build {
  sources = ["source.null.example"]

  provisioner "shell-local" {
    inline = [
      "echo ${trimspace(local.result)} == olleh",
    ]
  }
}

External Program Protocol

The protocol is similar to the one used by the external data source. However, query and result are plaintext strings instead of JSON objects. Refer to the external doc for more details.

external-raw should be used over external in cases where the external program does not support JSON input and/or output.

Argument Reference

Required

command ([]string) - A list of strings, whose first element is the program to run and whose subsequent elements are optional command line arguments to the program. Packer does not execute the program through a shell, so it is not necessary to escape shell metacharacters nor add quotes around arguments containing spaces.

Optional

working_dir (string) - Working directory of the program. If not supplied, the program will run in the current directory.
query (string) - An input to pass to the external program. If not supplied, the program will not receive anything on standard input.

Output

result (string) - The output returned from the external program.